The invention relates to a support housing for exhaust gas turbochargers which can be placed on an internal-combustion engine and, more particularly, to a support housing for at least two exhaust gas turbochargers which can be placed on an internal-combustion engine. The exhaust gas turbochargers are each constructed with two blade wheels arranged on a common shaft. One blade wheel is arranged in a compressor housing and the other is arranged in a turbine housing. The common shaft is in each case disposed in a bearing housing arranged between the compressor housing and the turbine housing. The turbine housings of the exhaust gas turbochargers form flow spaces which each comprise a spiral duct, an adjoining, radially interior blade wheel duct and an axially directed outlet duct. The support housing is constructed as a box-type supporting device for the exhaust gas turbochargers which contains a hollow space and on which the exhaust gas turbochargers are fastened. The compressor housings are arranged outside the hollow space and the turbine housings are arranged inside the hollow space. Recesses for passing-through the shafts of the exhaust gas turbochargers are provided in the walls of the support housing as well as openings for feeding and removing the exhaust gases to and from the turbine housings.
A support housing of the above described type is known from German Patent document DE 34 39 738 C2. In the case of this known supercharged internal-combustion engine, the turbine housing of the exhaust gas turbocharger is arranged in a hollow space formed by a support housing. The compressor housing of the exhaust gas turbocharger is disposed outside the hollow space. For the purpose of fastening, the exhaust gas turbocharger is received, together with its bearing housing, in a cylindrical recess of the lateral wall of the support housing. The exhaust gas turbocharger is fastened on the support housing by using screws. This cylindrical recess for receiving the bearing housing is formed by two semicircular recesses having an upper and a lower part on the edges. On the edges of the upper and lower part, the support housing is composed. When the upper part is taken off, the exhaust gas turbocharger can be inserted in the recess at the lower part for assembly purposes. The assembly can be completed when the upper part is fitted back on.
The bearing housing of an exhaust gas turbocharger according to German Patent document DE 35 32 695 C1, is at the same time, constructed as an engine support arranged between an elastic bearing and the internal-combustion engine. In this dual function as a bearing housing and as an engine support, a savings in components is achieved which has corresponding advantages. However, it is not always possible or desirable to arrange an exhaust gas turbocharger in an area of the internal-combustion engine in which the bearing housing is used as an engine support.
In the case of a supercharged internal-combustion engine according to German Patent document DE 30 05 655 C2, a support housing placed on the internal-combustion engine, which is composed of a lower part and an upper part, is also used for the space-saving fastening of exhaust gas turbochargers. In this case, the turbine housings of the exhaust gas turbochargers and the corresponding exhaust gas pipes are arranged inside a hollow space formed by the support housing. The compressor housings with the corresponding charge air pipes are situated outside the hollow space. The exhaust gas turbochargers, which are arranged with horizontal axes, are disposed in the area of the bearing housings in semi-cylindrical recesses of the edge areas of the upper and the lower part. The upper and lower parts rest against one another in a horizontal dividing joint. When the upper part is removed, an exhaust gas turbocharger can be inserted for assembly purposes in the recess on the bottom part and, after the upper part is fitted back on, can be fastened by means of screws on the upper and the lower part.
In the case of the example in German Patent document DE 30 05 655 C2, wherein a charger arrangement consists of two groups for two-stage charging, the support housing encloses four turbine housings which are arranged with respect to a perpendicular axis of the support housing in a centrically symmetrical manner in a support housing. The support housing is also constructed in a centrically symmetrical manner. It is considered a disadvantage of the known support housing construction that it consists of differently constructed components which are expensive to manufacture because correspondingly different tools must be made available for the manufacturing. For the case of a conventional cast construction different form tools are required. These different tools are expensive.
There is therefore needed a simplified manufacturing and mounting for a support housing, while achieving a space-saving construction which thus makes it less expensive.
These needs are achieved according to the present invention by providing a support housing for at least two exhaust gas turbochargers which can be placed on an internal-combustion engine. The exhaust gas turbochargers are each constructed with two blade wheels arranged on a common shaft. One blade wheel is arranged in a compressor housing and the other is arranged in a turbine housing. The common shaft is in each case disposed in a bearing housing arranged between the compressor housing and the turbine housing. The turbine housings of the exhaust gas turbochargers form flow spaces which each comprise a spiral duct, an adjoining, radially interior blade wheel duct and an axially directed outlet duct. The support housing is constructed as a box-type supporting device for the exhaust gas turbochargers which contains a hollow space and on which the exhaust gas turbochargers are fastened. The compressor housings are arranged outside the hollow space and the turbine housings are arranged inside the hollow space. Recesses for passing-through the shafts of the exhaust gas turbochargers are provided in the walls of the support housing as well as openings for feeding and removing the exhaust gases to and from the turbine housings. The bearing housings of the exhaust gas turbochargers are integrated into the walls of the support housing.
In this manner, the support housing is therefore constructed such that, not only can the exhaust gas turbochargers be fastened on it and the exhaust gas turbine housings be arranged in a hollow space, but also that it contains the bearing housing in which the shafts of the exhaust gas turbochargers are disposed. It also contains the ducts required for the lubrication of the bearings and is used as a protective housing for the bearing components. The bearing housings are therefore no longer separate components so that the number of required components is reduced whereby the manufacturing and assembly is naturally simplified.
It is particularly advantageous for the support housing to be developed as a cast construction with molded-in bearing housings. In order for the support housing to be accessible from the interior side, it is composed of at least two parts. In this case, it is advantageous not to place the dividing joint in areas in which an exhaust gas turbocharger is to be fastened. This is done so that none of the bearing housings of the exhaust gas turbochargers are divided. This construction is favorable for the assembly. In this case, it is advantageous for the support housing to be divided in a plane in parallel to a perpendicular axis. The exhaust gas turbochargers can then be fully mounted on the housing parts before the housing parts are assembled to form the support housing. It is further advantageous for a symmetrical support housing that the number of components be limited further, and the manufacturing be made still less expensive. This is because both housing parts, i.e., two symmetrical parts, for a support housing may, in each case, be produced using the same tool. The housing parts rest against one another in a dividing joint which is situated in a plane extending in the central perpendicular axis of the support housing. When such symmetrical housing parts are used, the tool costs are reduced because fewer different tools are required. At the same time, the mounting and storage is simplified as a result of the same components being used for both housing parts.
The support housing can be constructed in a particularly space-saving manner when the housing parts consist of two housing parts which are centrically symmetrical with respect to the perpendicular axis and on which the exhaust gas turbochargers are also arranged in a centrically symmetrical manner.
Two groups of two-stage exhaust gas turbochargers can be arranged in a space-saving manner while the mounting is simple if one high-pressure and one low-pressure exhaust gas turbocharger is assigned to each housing part of the support housing. The longitudinal axes of these turbochargers are situated at an acute angle with respect to one another when viewed in the direction of the perpendicular axis.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.